Question
Possible external IP addresses for my k8s cluster
- Posted on November 6, 2023
- NetworkingKubernetes
Asked by Kyle Loveless
Hi, some API providers (e.g. for a database), allow you to configure a filter on their side to only accept traffic from certain IP address blocks.
Is there a reasonable way to restrict the set of IPs my k8s cluster uses when sending traffic outside of the cluster such that I could configure this list?
I’m aware this is support for reserved IPs, but not clear how integrated it is with k8s (https://docs.digitalocean.com/products/networking/reserved-ips/how-to/outbound-traffic/).
Or if not, possibly the DigitalOcean-wide set of IP addresses that may be used, thus limiting attacks to running on DigitalOcean?
Thanks!
Kyle
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Hi there,
Indeed with Kubernetes, especially on cloud platforms like DigitalOcean, the outgoing traffic from the cluster typically originates from a range of IPs that are dynamically allocated by the cloud provider.
DigitalOcean does support reserved IPs, and these can be used to ensure that outbound traffic from your cluster comes from a predictable IP address. But that is mainly for Droplets.
To implement this with a DOKS cluster, one option would be to use a Static Routes Operator as described here:
Another option is to use an Egress Gateway via Crossplane with DigitalOcean CRD. Here is a guide on how to do that:
I could suggest testing this out on a staging or a test cluster before trying the implementation on your production environment!
Hope that this helps!
Best,
Bobby